1. Field of the Invention
The present invention relates generally to rotating turbomachinery, such as turbochargers, and, more particularly, to an improved arrangement for mounting and securing an impeller wheel of such turbomachinery to a rotating shaft and limiting axial movement of the impeller wheel on the shaft during operation of the turbomachine.
2. Description of Related Art
In rotating turbomachinery such as turbochargers, impeller wheels are mounted to a rotating shaft, which is driven at high rotational speed. For example, a diesel engine turbocharger typically includes a turbine which drives a shaft and a compressor mounted for rotation on the shaft opposite the turbine wheel. The compressor typically includes an impeller wheel mounted for rotation on the shaft. The impeller wheel is driven at high rotational speeds by the rotating shaft during operation of the turbocharger. Numerous mounting arrangements are known in the field of rotating turbomachinery, also referred to herein generally as turbomachinery, for mounting and/or securing an impeller wheel to a rotating shaft. A few examples of such mounting arrangements are discussed herein.
U.S. Pat. No. 6,481,917 to Chen et al. discloses an arrangement for mounting an impeller wheel, such as a turbine or compressor wheel, on a shaft. In the mounting arrangement disclosed by this patent, the impeller wheel is held in place on the shaft by a plurality of clamping rings. One of the clamping rings engages a recess in the hub of the impeller wheel, while a second clamping ring engages a similarly formed recess at the opposite end of the impeller wheel hub. The first clamping ring is held in place against the impeller wheel by a threaded nut and engages a plurality of Belleville spring washers.
U.S. Pat. No. 5,961,246 to Mitsubori discloses a simple coupling bushing for joining an impeller wheel to a shaft.
U.S. Pat. No. 5,163,816 to Goetzke et al. discloses another example of a mounting arrangement for mounting an impeller wheel on a drive shaft. The mounting arrangement disclosed by this patent includes a two-piece spacer which is used to secure the impeller wheel to the drive shaft. The drive shaft includes a journal. The two-piece spacer is provided between the journal and the impeller wheel. The two-piece spacer includes a flange member and an annular locking ring. The annular locking ring is disposed in a recess formed in the flange member, and between the flange member and the impeller wheel. The locking ring includes a projection that engages a recess in the impeller wheel. The projection engages a tubular sleeve provided between the impeller wheel and the shaft. The annular locking ring further engages spline recesses formed in the drive shaft.
U.S. Pat. No. 3,884,595 to Herrick discloses a further example of an impeller wheel and shaft mounting arrangement. In the mounting arrangement disclosed by this patent, the shaft is provided with a keyway which receives a key. A hub portion of the impeller wheel is also provided with a keyway, which receives the same key. The key prevents relative rotation between the impeller wheel and the shaft.
U.S. Pat. No. 2,960,939 to Buschhom et al. discloses a rotor attachment arrangement for centrifugal pumps. In the attachment arrangement disclosed by this patent, a locking ring is provided in an annular groove in a pump shaft. The locking ring extends into a recess formed in a shaft-protecting sleeve positioned about the pump shaft. The locking ring prevents movement of the pump shaft relative to the sleeve by engaging a shoulder formed in the sleeve and a key formed on the pump shaft.
While numerous attachment or mounting arrangements are known in the art for connecting an impeller wheel to a rotating shaft, a continuing need still exists in the field of rotating turbomachinery for improved impeller-shaft mounting or attachment methods, particularly those that are simple to manufacture and install in such rotating turbomachinery. A specific need exists for an improved mounting arrangement for mounting and/or securing an impeller wheel to a rotating shaft that will limit axial movement of the impeller wheel on the shaft, which occurs during operation of the turbomachine.